This invention relates to turbulators to be utilized in an environment wherein reducing the pressure drop across the turbulator is important. One particularly preferred application is in a high-stage generator for an absorption chiller/heater wherein the heat source is the exhaust of an engine such as a micro-turbine.
Refrigerant absorption cycles have been used for decades to provide a cooled or heated water source for environmental temperature control in buildings. As is known, an absorber and an evaporator in a refrigerant absorption cycle selectively receive a concentrated absorption fluid, such as a LiBr solution, and a separate refrigerant (often water), respectively. The absorption fluid is selectively dropped onto separate tube sets in the absorber and absorbs the refrigerant vapor generated from the evaporator. A dilute solution, containing both the absorption fluid and the refrigerant is then returned to a generator for generating a heated, concentrated absorption fluid. In the generator, a driving heat source drives the refrigerant vapor out of the mixed fluid. From the generator, the absorption fluid and removed refrigerant vapor are separately returned to the absorber and the evaporator, respectively.
The above is an over-simplification of a complex system. However, for purposes of this application, the detail of the system may be as known. Further, while the above-described system provides chilled water, absorption cycles are also utilized to provide heated water for heating of a building. This invention would extend to such systems. For purposes of this application, an absorption chiller and an absorption heater are to be defined generically in the claims as an “absorption solution/refrigerant system” . A worker of ordinary skill in the art would recognize the parallel absorption heater systems and how such systems differ from the disclosed chiller system.
These systems deliver the heated exhaust air to a number of channels known as “smoke tubes” . The smoke tubes are positioned between a number of flow passages that communicate the absorption mixture around the smoke tubes to transfer heat to the absorption fluid.
In the prior art, the turbulators have blades secured to an elongated member. The blades typically have rectangular flanges at a normal angle relative to a central web. The blades provide good heat transfer characteristics. However, in the prior art, the source of heat has been a dedicated source of heat. At times, it may be useful to utilize a source of exhaust heat generated from another separate system to provide the heated fluid. As an example, it may be desirable to utilize the exhaust of a micro-turbine to provide the heat source. The prior art rectangular flanges, in both their shape and arrangement, create a downstream wake region, which increases the pressure drop across the smoke tube. This increase in pressure drop can provide efficiency concerns back upstream to the prime mover (i.e., the micro-turbine). This is undesirable.